1. Field of the Invention
The present invention relates to a light source device with a high layout efficiency.
2. Description of the Related Art
Recently, space saving, lower power consumption, and higher luminance have been required for thin tubular light sources, and development thereof has been under way. Such a light source is disclosed in, for example, Jpn. Pat. Appln. KOKAI Publication No. 2006-173324.
In Jpn. Pat. Appln. KOKAI Publication No. 2006-173324, a high-performance light source device satisfies both high color rendering properties and high luminous efficiency that are in a trade-off relation.
This light source device includes a first semiconductor laser light source, a wavelength converting member, at least one first unit having a light guide, a second semiconductor laser light source, and at least one second unit having a wavelength converting member and a light guide.
The first semiconductor laser light source has a laser element which emits primary light of a blue wavelength region.
The wavelength converting member has one or more kinds of fluorescent substances. The fluorescent substance absorbs the primary light emitted from the first semiconductor laser light source, converts the wavelength thereof, and radiates light having a wavelength region longer than that of the primary light. This wavelength converting member functions as an illumination unit.
In the section of the light guide, the refractive index in the center is higher than the refractive index in the peripheral portion. The light guide guides the primary light emitted from the first semiconductor laser light source to the wavelength converting member.
The second semiconductor laser light source emits primary light having a wavelength region shorter than that of the primary light that the laser element emitted.
This light source device is provided in a tubular observation device, and the illumination unit is mounted at the distal end portion of the tubular observation device together with a second functional unit. The second functional unit has, for example, an imaging unit and an opening portion. This opening portion is provided, for example, to insert an optional member through the distal end portion. The tubular observation device is, for example, an endoscope.
FIG. 7A and FIG. 7B show front views of a distal end portion 191 (case) of a general tubular device 190. As shown in FIG. 7A, for example, the distal end face of one functional unit 181 and two illumination units 143 are provided in a distal end face 171 of the distal end portion 191. As shown in FIG. 7B, for example, the distal end faces of two functional units 181 and two illumination units 143 are provided in a distal end face 171 of the distal end portion 191. The functional units 181 are, for example, an imaging unit and an opening portion.
In general, a distal end portion of the light guide has a circular shape. In general, the illumination unit 143 has a cylinder shape. Therefor primary light is emitted from the light guide in circular shape.
As shown in FIG. 7A and FIG. 7B, in general, the distal end portion 191 has a cylinder shape and the distal end face 171 has a circular shape for matching to emitting shape of primary light. As shown in FIG. 7A and FIG. 7B, in general, the distal end face 171 has a circular shape, the distal end portion 191 has a cylinder shape.
As shown in FIG. 7A and FIG. 7B, when the functional units 181 and the illumination unit 143 are provided adjacent to one another, a fill factor in the distal end portion 191 including distal end face 171 is decreased, a dead space is formed. That is, wasteful space is occurred and layout efficiency is decreased in the distal end portion 191 including distal end face 171.
The present invention has been made under these circumstances, and an object of the invention is to provide a light source device which the formation of dead space is suppressed, wasteful space is eliminated, and layout efficiency is increased in the part in which the light source device is provided.